This is an extremely powerful & versatile language, but you do have to be reasonably familiar with Perl to be able to really take advantage of it. One feature that I find particularly useful is that the developers have made it quite easy to extend it with your own c sub-routines (see PDL::PP). This gives you the best of both worlds, a high level scripting language, with many built-in functions, for ease of idea developement and a compiled language that quickly handles any customized processor intensive stuff.
This is not just a poorman's Matlab(C), but a hell-serious math package ! It is really mature and horribly fast. I wrote a 3d continous CA within hours. The learning curve is significant, but its power is overwhelming. The mailing list is extremly responsive and the developers are great. Surely its intensive use in serious astronomic/academia projects boosted its versatility and design.